CAMBRIDGE, Md. — President Barack Obama warned once again that he wants to work with Republicans in Congress to pass needed legislation, but he “will not wait” to take action if that doesn’t happen.

The president also suggested that passage of Obamacare — his signature legislative victory — would be seen as a “monumental achievement” in the future, and he thanked House Democrats for backing the bill.

“I think 10 years from now, five years from now, people will look back and say this was a monumental achievement, and it could not have happened had it not been for this caucus,” Obama declared.

Obama said his mission, and that of all Democrats, is to provide opportunities for all Americans to move ahead in their lives.

“I want to work with Congress to make that happen, but I’m not gonna wait because there’s too much to do,” Obama said in a 10-minute address to dozens of Democratic lawmakers gathered on Maryland’s Eastern Shore.

“Sometimes the debates on Capitol Hill get so abstract,” Obama added. “We can get a whole lot more done if we’ve got Congress working with us.”

Obama repeatedly called for an increase in the federal minimum wage to $10.10 per hour. The initiative is part of a major Democratic political offensive heading into the midterm elections.

On Wednesday, Obama issued an executive order to raise the minimum wage for some government contractors. Republicans have objected to such legislation, arguing it could hurt employers.

Obama broke little new ground in his Friday appearance, reiterating many of the themes he had touched on in his State of the Union address.

The president called for passage of immigration reform legislation. Speaker John Boehner and other top House Republicans have said they may not move on the issue this year.

“That’s got to be a top priority,” Obama said. The president also said he understood the political challenges facing Republicans on the issue, but said Congress had to act.

After the media was escorted from the room, Obama took some relatively gentle questions from rank-and-file Democrats, who had just spent several hours at the White House last week. At one point, Obama joked that it was Presidents Day on Monday, which Obama renamed “Be Nice to a President Day,” according to sources in the room.

Obama was asked for federal assistance for drought-stricken California, along with help in publicizing positive news related to Obamacare.

Obama also warned Democrats that they were “in the penalty box” with voters over the botched rollout of the ACA website, but overall, he trumpeted good news on the program. More than 3 million Americans have signed up for health care through state and federal exchanges, the administration announced earlier this week.

The president cautioned Democrats that there are “outer limits to what we can do by executive action,” especially on immigration reform, said a Democratic aide. He urged them to continue to press House Republicans to take up the issue this year. “Don’t take your foot off the pedal,” Obama said, according to the source.

Obama also was pressed on what the future U.S. role in Afghanistan would be, according to sources in the closed-door session.

“President Karzai has been challenging,” Obama admitted, referring to the Afghan leader.

U.S. officials were infuriated this week by the Afghan government’s decision to release dozens of prisoners suspected of attacking American and allied forces. The White House has also been unable to reach a deal with Karzai on a Status of Forces agreement that would allow U.S. troops to remain in the country beyond the end of 2014, Obama’s planned withdrawal date.

In an earlier appearance, Vice President Joe Biden delivered his own upbeat message to House Democrats, telling them the United States and the Democratic Party are in great shape.

“I’m optimistic about America’s prospects, and I’m optimistic about our prospects,” Biden told dozens of House Democrats in a morning speech.

Like House Minority Leader Nancy Pelosi (D-Calif.), Biden said Democrats are better positioned to deal with the needs of the American public, especially on issues like pay equity for women, immigration reform and increasing the minimum wage.

“I think it would be a sin if we didn’t talk about income equality,” Biden said. He suggested Republicans would cut taxes for the rich and slash entitlement programs if they won control of both the House and Senate on Election Day, dismissing those ideas as some of the “ridiculous policies from our friends on the right.”

Biden also suggested that the internal battles within the GOP have left it leaderless and adrift, as well as being unable to strike legislative bargains with President Barack Obama and Democrats on Capitol Hill.

“There is no Republican Party,” Biden asserted. “I wish there were.”

Biden noted that he would campaign for Democratic incumbents and challengers throughout the year. Biden recently met with Democratic Congressional Campaign Committee Chairman Steve Israel of New York to discuss which districts he would appear in during the upcoming campaign season. Biden, in some ways, is better positioned to do so than Obama, especially in red states.

“Between now and November is three political lifetimes,” Biden said. “A lot has happened, and a lot will change.”

During a closed door question-and-answer session with Democrats after his speech, Biden was asked about U.S.-Asia relations, job growth and extending federal unemployment insurance, according to sources in the room.

Biden also assured Pelosi and other Democrats that the White House would move cautiously on the Trans-Pacific Partnership, which Pelosi and Senate Majority Leader Harry Reid have both opposed.

The White House, however, will not back off seeking “fast-track authority” on trade agreements.

And in a vintage Biden moment, the vice president was asked about storm damage in the U.S. Virgin Islands.

Biden told Del. Donna Christensen (D-V.I.), that he would be visiting the islands soon, and he promised to seek federal recovery aid.

“When I die, I want to be reborn in the Virgin Islands,” Biden quipped before walking out.